Magnetic control circuit



May 4, 1965 E. E. NEWHALL 3,182,297

MAGNETIC CONTROL CIRCUIT Filed Dec. 51, 1962 3 Sheets-Sheet 1 FIG.

B/AS SOURCE COIWWOL MEANS 0/?! V5 SOURCE FIG. 3

1' INPUT m if??? 2 53'? F--A\ DRIVE DRIVE MME t BIAS B/AS I t t1 #2 4 st ADVANCE ADVANCE RESET RESET l/Vl/EN TOR By E. E. NEW/ ALL ATTORNEY May4, 1965 E. E. NEWHALL MAGNETIC CONTROL CIRCUIT 5 Sheets-Sheet 2 FiledDec. 31 1962 May 4, 1965 E. E. NEWHALL MAGNETIC CONTROL CIRCUIT sSheets-Sheei 3 Filed Dec. 51, 1962 Q: g M

T mm L T mwwt a L T MQI WRTISQ QQEEDU United States Patent 3,182,297MAGNETIC CONTROL CIRCUIT Edmunde E. Newhall, Brookside, N.J., assignorto Bell Telephone Laboratories, Incorporated, New York, N.Y., acorporation of New York Filed Dec. 31, 1962, Ser. No. 248,456 13 Claims.(Cl. 340-174) This invention relates to magnetic information storage andtransfer circuits. More particularly, this invention relates to thetransfer of information from one location in a magnetic structure toanother.

Various magnetic elements such as the toroidal core, the transfluxor andthe ferrite sheet have been employed as the basic unit upon whichmagnetic circuits have been generated, typically for informationhandling. The general relating characteristic of these elements is thatthey are composed of materials having substantially rectangularhysteresis loops and thus exhibit two maximum remanent, stable magneticstates and associated switching thresholds.

The toroidal core offers one magnetic fiux path acting as a simpleelectrical-magnetic transducer for electric pulses introduced theretothrough inductively coupled electrical conductors. Typically, one coreis coupled by an electrical conductor to a second core for the transferof information therebetween. A certain degree of complication isnecessary in the transfer circuit to avoid among other things thebidirectional propagation of the information between cores.

In the prior art, the transfluxor offers further versatility over thetoroidal core in that it prodvides a plurality of magnetic flux pathstherein. Transfluxors like the toroidal cores typically are connected byelectrical conductors for the transfer of information therebetween.However, in the case of transfiuxors the transfer circuit may be simplerbecause the internal flux path structure is capable of carrying some ofthe burden carried in toroidal core arrangements by the transfercircuit.

The transfer circuits for both toroidal cores and transfiuxors typicallyare wired by hand and consequently there is considerable expenseinvolved. The ferrite sheet offers the possibility that the transfercircuit can be avoided altogether. We are concerned here primarily withthe transfer of information from one location to another in a ferritesheet. 7

One of the major continuing problems in the information handling art isthe expeditious transfer of information from one location to another as,for example, in a ferrite sheet. More specifically, information, forexample, in the ladder-shaped ferrite sheet or laddic disclosed inPatent No. 2,963,591 of T. H. Crowley and U. F. Gianola, issued December6, 1960, is transferred from location to location through flux carryinglegs. However, under certain circumstances this transfer may be attendedby flux leakage which may result in the attenuation of flux inducedtherein and propagated therealong. More particularly, a binary inputsignal inducing a prescribed fiux condition to the first rung of such aladder-shaped structure may be transferred in the form of flux to apreselected remote rung by switching the flux in the first rung by asuitable drive pulse and holding fixed the flux in all the intermediaterungs. The lowest reluctance path available to the flux switched in thefirst rung is through the preselected rung. However, this preselectedrung is in parallel with rungs which may permit some flux leakage. Insuch cases, only a portion of the flux switched in the first leg istransferred to the preselected remote rung. Accordingly, in structuressuch as ferrite sheet shift register circuits which may require a largenumber of such rungs, the flux switched in successive preselected rungsduring successive phases of operation of the shift register may becharacterized by an accumulating flux loss which eventually results inthe loss of the binary signal identity therein. The loss of the binarysignal identity can, of course, be prevented by providing fluxamplification means at suitable points along the flux path. Typically,such amplification means includes transistors or other similarcomponents and accompanying circuitry and, accordingly, is expensiverelative to all-magnetic amplification, that is, amplification of thebinary signal within the ferrite sheet.

An object of this invention is the all-magnetic amplification of binarysignals.

A more specific object of this invention is the transfer of informationin the form of an internally regenerated remanent flux condition fromone address to another in a ferrite sheet.

Another object of this invention is a new and improved ferrite sheetshift register.

The foregoing and other objects of this invention are realized in onespecific embodiment wherein a ferrite sheet is apertured to form a pairof side rails and four transverse interconnecting legs therebetween,thus defining an ordered sequence of three apertures. A winding means isenergy coupled to the second interconnecting leg for causing repeatedflux switching therein when activated by first and second pulses.Further windings are provided to each of the four interconnecting legsfor preferring, when properly activated, the fourth leg for the fiuxclosure path when the second leg is switched to one maximum remanentstate, and for preferring the third leg when the second leg is switchedpartially toward the other maximum remanent state, thus accumulating inthe fourth leg flux in increments for the ultimate switching of fluxthere.

Thus, in accordance with this invention, it is a feature thereof thatfiux is transferred in increments from a transferor to a transfereelocation in a ferrite sheet.

In accordance with the principles of this invention, it is a featurethereof that the transferor portion of a ferrite sheet be switched fromone magnetic state to another repeatedly while the transferee portion isbiased to undergo, synchronously with the switching, a prescribed changein flux closure path provided for the flux switched in the transferorportion.

In accordance with an embodiment, it is another feature of thisinvention that the transferor and transferee locations be controllably,magnetically separable from remaining portions of the ferrite sheet.

The invention and the further objects and features thereof will beunderstood more fully with reference to the following descriptionrendered in conjunction with the accompanying drawing, wherein:

FIG. 1 depicts an arrangement of a ferrite sheet including transferorand transferee locations within an information address and theaccompanying circuitry by which information is transferred therebetweenin accordance with this invention;

FIGS. 2a, 2b, 2c, 2d, and 2e illustrate the changes in flux distributionin the various legs of the ferrite sheet during the operation of thearrangement of FIG. 1 in accordance with this invention;

FIG. 3 depicts the time sequence of the applied pulses for thearrangement of FIG. 1 in accordancewith this invention; and

FIG. 4 depicts a shift register based on the modular arrangement of FIG.1.

It is to be understood that the figures are not necessarily to scale,certain dimensions being exaggerated for purposes of illustration only.

The invention, its structural requirements and operation can best bedescribed in terms of a basic module from which practical embodimentsare produced by repetition and interconnection. Accordingly, FIG. 1depicts a portion 10 of a ferrite sheet apertured to form a pair of siderails 11 and 12 and four interconnecting legs 13, 14, 15 and 16, thusforming an ordered sequence of three apertures 17, 18 and 9. Each of theside rails and legs is taken as having the same minimum crosssectionalarea and thus the same flux carrying capacity. Although the ferritesheet is shown partially extended in each direction along the line ofthe apertures, the above referenced elements comprise the basic magneticmodule in accordance with this invention, the extensions serving only toillustrate the interconnection of the module with additional modules aswill become apparent hereinafter. In this module, side rail 11 isdivided by an additional aperture 20 adjacent aperture 18. The aperture20 provides in side rail 11 thereabout a circular flux path includinglegs 21 and 22, each having a minimum cross-sectional area of half thatof the other legs of the structure and thus half the flux carryingcapacity thereof. Accordingly, there is formed a gate 23 similar to thatdescribed in the copending application of D. B. Armstrong and U. F.Gianola, Serial No. 818,146, filed June 4, 1959.

A conductor 24 is inductively coupled to leg 14 by winding 25 and isconnected to a variable amplitude drive pulse source 26. A conductor 27is inductively coupled to both legs 21 and 22 by a figure S winding 28and connected to the variable amplitude drive pulse source 26. Aconductor 29 is coupled serially in a like sense to legs 13 and 15 andin an opposite sense to leg 16 by windings 30, 31 and 32, respectively,and is connected to variable amplitude bias pulse source 33. A conductor34 is coupled serially and in an alternating sense to legs 13, 14, 15and 16 by windings 35, 36, 37 and 38, respectively, and is connected tothe variable amplitude bias pulse source 33. The pulse sources 26 and 33are controlled by a synchronizing and control means 39. The pulsesources 26 and 33 may comprise any pulse source well known in the artsuitable for providing the necessary pulses as described herein.Accordingly, the pulse sources will not be described in detail, thedescription of their function being sufiicient for a completeunderstanding of this invention. Similarly, control means 39 maycomprise any known means for effecting coincident bias and drive pulsesand providing the proper timing for applied pulses as described herein.The sense of the coupling windings, the direction of flux, the drivepulses and resulting changes of flux will be understood more fully fromthe following description of the operation of the arrangement of FIG. 1rendered in conjunction with FIGS. 2a through 2e and 3.

Basically, this invention is concerned with the transfer of informationin terms of a particular flux pattern from one location in a ferritesheet to another. Consequently, one test in determining the efficacy ofa particular arrangement is to examine during operation thereof theinitial, intermediate and final flux patterns, tracing the changestherein in response to the applied pulses and comparing the finalpattern with the desired results.

FIGS. 2a through 22 are a sequence of apertured ferrite sheet portionscorresponding to portion 19 of FIG. 1 and depicting therein the initial,intermediate and final flux patterns for legs 13, 14, 15 and 16 of FIG.1 assuming the presence of a degenerate, stored binary one in a locationdefined by legs 13 and 14 and a binary zero in a location defined bylegs 15 and 16. In this connection the term degenerate characterizes apartially switched flux condition in a leg or pair of legs as isdescribed more fully hereinafter. Input means for providing this storedone in the case illustrated by FIG. 1 would be a terminal leg of apreceding module as shown in FIG. 1.

For the purposes of the description of the operation of the arrangementof FIG. 1, it will be assumed that an initial normal flux distributionis present in structure of FIG. 1 when the leg pairs 13-14 and -16include flux in the counterclockwise direction as shown by the dottedlines and arrows in FIG. 1. Thereafter, the flux distribution is asrepresented by the broken lines in the various legs of the structure asshown in FIG. 2a, for example. Each of the lines is taken to representonehalf of the total flux value which can be induced in a particular legand the arrows indicate the polarity of the flux present. Since each ofthe legs and side rails is fluxlimited to the same degree in view of theequal minimum cross-sectional areas, the flux magnitude represented bythe broken flux lines is thus consistent in each case. The clear fluxdistribution assumed then is one in which a maximum remanent flux ispresent in the structure 10 of FIG. 1 in closed loops through theadjacent legs as shown. In accordance with the fiux behavior conventionto be assumed in describing the operation of this invention, oppositelydirected lines within a single leg, where they occur hereinafter, may beregarded as oppositely poled fluxes which find closure by linking withother such fluxes in the same or other legs. Accordingly, a degenerate,stored binary one is assumed to be present when legs 13 and 14 includesome flux in a clockwise direction shown initially as oppositelydirected lines in FIG. 2a for legs 13 and 14. In addition, it is assumedfor convenience that each leg and side rail carries one unit of flux inorder to provide a magnetic structure wherein each of the possible fluxclosure paths is flux limited to the same flux magnitude. The efficacyof the arrangement of FIG. 1 is illustrated then if the degenerate,stored binary one can be transferred to legs 15 and 16 in a regeneratedcondition, that is, if all flux in legs 15 and 16 can be switched from acounterclockwise direction to a clockwise direction.

The desired switch in the direction of flux in legs 15 and 16 isaccomplished by the sequence of electrical pulses which induce themagnetomotive forces shown in FIG. 3 which is a plot of magnetomotiveforce (or M.M.F.) versus time t. Initially, a bit pulse terminatnig attime designated t may be provided by, for example, a preceding magneticleg switched in accordance with prior operation by electrical pulsesinductively coupled thereto to introduce a degenerate one into legs 13and 14. Subsequently, a bias pulse and a larger amplitude drive pulseare applied coincidently to conductor 29 by bias source 33 and toconductor 24 by drive source 26, respectively. Both the drive and biaspulses terminate at time t Then, coincident bias and drive pulses areapplied to conductors 34 and 27 by way of bias and drive sources 33 and26, respectively. Both these drive and bias pulses terminate at time tThe first coincident bias and drive pulses constitute an advance phaseof operation; the second coincident bias and drive pulses constitute areset phase, both phases in a single cycle of operation to be describedmore fully hereinafter. The direction of current from sources 26 and 33is chosen during the first bias and drive pulses to bias legs 13 and 15upward, leg 16 downward, to bias legs 21 and 22 to the right, and todrive leg 14 upward, each of the directions as viewed in the drawing. Inthis connection, the term bias refers to a pulse of an amplitudesufiicient only to drive a leg of magnetic material just short of itsswitching threshold. Thus the bias pulse produces in the magneticstructure a magnetic condition which adds to or subtracts from thatproduced by a coincident drive pulse, depending on the relative polarityand/or sense of magnetic coupling of the corresponding windings (asshown), to prefer or deter respectively the passage of flux alongprescribed paths. Similarly, during the second coincident bias and drivepulses the flux in gate 23 is driven to complete a flux closure pathabout the circular flux path there, legs 13 and 15 are biased upward andlegs 14 and 16 are biased downward, the directions again being as viewedin the drawing. In other words, during the first or advance phasecorresponding to the coincident bias and drive pulses terminating attime t the preferred flux closure path comprises leg 14, gate 23 and leg16. During the second or reset phase correspond ing to the coincidentbias and drive pulses terminating at time t the preferred flux closurepath comprises leg 14, gate 23 and leg 15. Thus in the first cycle ofperation comprising one advance and one reset phase, the flux in leg isswitched once to the maximum positive remanent condition as shownbecause of the drive pulse applied to leg 14 and an additional timepartially in the opposite direction of fiux as shown because the drivepulse applied to conductor 28 forces gate 23 to go to neutral providingenergy to leg 14 sufficient, when added to the energy provided by thecoincident bias pulse, to enable leg 14 to switch.

The elfect of the applied pulses of FIG. 3 on the flux distribution inthe magnetic sturcture can be understood most clearly in terms of FIG. 2where complete flux closures are diagrammed to facilitate one manner ofunderstanding the flux behavior during the present operation.Specifically, at time 1 shown in FIG. 3, the flux in legs 13 and 14 ofFIG. 2a is partially in a clockwise direction depicted in FIG. 2a asoppositely directed lines and corresponding to a stored degenerate,binary one. Flux closures and linkages in the flux-limited path may beunderstood as being completed as depicted by the connection of theoppositely directed lines of legs 13 and 14 as shown in the figures. Allthe flux in legs 15 and 16 is in the counterclockwise directioncorresponding to a stored zero. Flux closures about legs 15 and 16 areshown again by the connection of oppositely directed lines. The flux inlegs 21 and 22 at time i is in a circular flux path closing aboutaperture as shown, while the flux in the remaining portion of the siderail 12 beneath aperture 18, as viewed in the figure, closes upon itselfas shown.

FIG. 2b illustrates the flux distribution at time t as shown in FIG. 3.It will be remembered that the coincident advance bias and drive pulsesterminating at time t bias legs 13 and 15 upward, leg 22 to the rightand drive leg 14 upward. Consequently, leg 14 is switched upward or tothe maximum positive remanent condition as shown in the figure. Legs 22and 16 provide the flux closure path accommodating the flux changesoccasioned by the switching of leg 1s. Thus, during the advance phase ofthe first cycle of operation, a relatively long flux closure paththrough leg 16 is preferred for the fiux switched in leg 14.

FIG. 20 illustrates the flux distribution at time i as shown in FIG. 3.lit will be remembered that the coincident reset bias and drive pulsesterminating at time t bias legs 13 and 15 upward, legs 14 and 16downward, and drive the fiux in gatE 23 into the circular flux paththere, that is, switch the flux in leg 22. Consequently, leg 22 isswitched to the left, leg 15 is switched upward and leg 14 is switcheddownward as viewed in the figure.

At this juncture in the operation, the first cycle of operation inaccordance with this invention is completed. It should be noticed thateach of legs 13, 14, 15 and 16 now includes oppositely directed lines.Thus, during the first cycle of operation a degenerate one has beentransferred to legs 15 and 16. Moreover, during the advance portion ofthe first cycle of operation a relatively long flux path through leg 16was preferred by the bias pulse as applied while leg 15 was excludedthereby from the flux path. During this same period the flux in leg 14was switched to the maximum positive remanent condition. On the otherhand, during the reset portion of the first cycle of operation, the biaspulse as applied prefers a relatively short flux closure path throughleg 15 while excluding leg 16 from the path. During this same period,the flux in leg 14 is switched to the partially downward condition asviewed in the figure.

FIG. 2d illustrates the iiux distribution at time t as shown in FIG. 3.The second coincident advance bias pulse and drive pulse, respectively,terminating at time t as was the case with the first advance pulses,biases legs 13 and 15 upward, biases leg 22 to the right and drives leg14 upward, all the directions being as viewed in the figure.Consequently, leg 14 is switched upward into '6 the maximum positiveremanent-condition as shown in the figure. Legs 22 and 16 again providethe flux closure path accommodating the flux changes occassioned by theswitching of leg 14.

FIG. 2e illustrates the flux distribution at time t as shown in FIG. 3.The second coincident reset bias pulse and drive pulse, respectively,terminating at time 1 as was the case with the first reset pulses,biases legs 13 and 15 upward, biases legs 14 and 16 downward, and drivesthe fiux in gate 23 into the circular flux path there, that is, switchthe flux in leg 22. Thus, leg 22 is switched to the left, leg 15 isswitched upward and leg 14 is switched downward as viewed in the figure.

The second cycle of operation is now complete. Again, during the advancephase, a relatively long flux path through leg 16 was preferred by thebias pulse asapplied. Also, during the reset phase, a relatively shortflux closure path through leg 15 was preferred by the bias pulse asapplied. As a result of the second cycle of operation, an additionalincrement of flux, shown conveniently as one-half unit of flux, istransferred to legs 15 and 16. Thus the final distribution as shown inthe figure comprises a fiux pattern in legs 13 and 14 corresponding to adegenerate, stored one as shown initially in FIG. 2a. However, legs 15and 16 now include fiux lines indicating maximum positive and negativeremanent conditions, respectively, corresponding to a regenerated,stored, binary one. Thus, in accordance with this invention,amplification of information in terms of flux patterns is providedwithin a ferrite sheet without the necessity of providing costly andpower consuming external amplifying circuits.

In the foregoing description, it was assumed that the input degenerate,binary one, was characterized by one-half the flux capacity of each legin the structure. However, conditions could exist where the input signalhas degenerated to less than the one-half value in which case the twocycles of operation described will insure continual build-up of thesignal for eventual regeneration thereof. Further, a particular bias anddrive circuit configuration was assumed in the foregoing description forillustrative purposes only. It is contemplated herein to include othercircuit configurations which permit operation in accordance with thisinvention. Moreover, the bias and drive pulses have been described asprovided coincidently, that is initiated and terminated simultaneously.However, it should be evident to one skilled in the art that the biaspulse may be initiated prior to the corresponding drive pulse. It isonly necessary that the various legs of the. structure M be in the biascondi-v tions described when the corresponding drive pulse is applied.

The operation of the arrangement of FIG. 1 in accordance with thisinvention has been described only for the condition where a singledegenerate one has been introduced because this invention is directed atregeneraitng such an input. In practice it is customary to introduce asequence of binary bits. Moreover, the sequence of bits includes bothbinary ones and binary zeroes. Accordingly, for practical use of thearrangement of FIG. 1, additional circuitry of a conventional type isrequired for accommodating a zero as well as a one in sequence.Additional bits are introduced by additional input cycles after twofirst cycles and two second cycles of operation in the sequence shown inFIG. 3. These four cycles are required to transfer binary information orbits from one information address to another as, for example, in a shiftregister, as will become apparent hereinafter.

A stored zero characterized as a clear flux condition is introduced insequence by the absence of a'pulse during the corresponding input cycle.As a consequence, the flux condition shown in legs 13 and 14 of FIG. 1is not altered thereby. During the following advance phase the drivepulse applied to leg 14 attempts to drive the flux in leg 14 in adirection in which the leg is already saturated. Again the clear patternremains undisturbed. During the following reset cycle as shown in FIG. 3the flux in gate 23 already is closed about the circular path and noflux change is produced by the drive pulse applied to gate 23 duringthis cycle. Thus at the end of two cycles of operation after theintroduction of a zero into the module of FIG. 1 the counterclockwise orclear flux pattern still remains in legs and 16.

The advantages of the circuit arrangement of FIG. 1 and its operationwill be understood more clearly from a description of the shift register111! of FIG. 4. Shift register is fabricated in a single ferrite sheetby what may be thought of as repetition and interconnection of aplurality of the basic module described in FIG. 1. The ferrite sheet isapertured to form a pair of side rails 111 and 112 and interconnectinglegs therebetween which can be though of in sets of four to correspondto the legs of the module of FIG. 1 and which are designated 113 114 115116 et cetera, with the subscript denoting the set. The legs form anordered sequence of the apertures which are designated 117, 115 and 119to correspond to apertures 17, 1S and 19 of FIG. 1 and repeating ntimes. The side rail 111 includes additional apertures 120 through 120adjacent every other aperture of the ordered sequence of apertures. Eachaperture 120 provides in side rail 111 thereabout a circular flux pathincluding legs 121 and 122 which have subscripts denoting its orderedsequence, thus forming gates 123 123 123 A conductor 124 is inductivelycoupled to each leg 114 n by a corresponding winding 125 l mg) in seriesand to a variable amplitude drive pulse source 126.

A conductor 127 is coupled serially to all the legs 121 and 122 whichhave odd numbered subscripts by Y a corresponding figure 8 winding 12%and is connected to variable amplitude drive pulse source 126.Similarly, a conductor 127 is coupled serially to all the legs 121 and122 which have even numbered subscripts by a corresponding figure 8winding 128 and is connected to variable amplitude drive pulse source125. A conductor 12 9 is coupled serially in a like sense to legs 113and 115 and in an opposite sense to leg 116 of each set of legs bywindings 13%, 131,, and 132 respectively, hearing additional subscriptsto correspond to the various sets of legs, and is connected to avariable amplitude bias pulse source 133. A conductor 134,, is coupledserially and in an alternating sense to each of legs 113, 114, 115 and116 by windings 136 137 and 133 respectively, bearing correspondingadditional subscripts, and is connected to variable amplitude bias pulsesource 133. A conductor 124- is coupled to each leg 116 I n by acorresponding winding 125 in series and is connected to variableamplitude drive pulse source 126. A conductor 129 is coupled serially ina like sense to legs 115 and 113 and in an opposite sense to leg 114 ofeach set of legs by windings 139 131 and 132 respectively, and isconnected to variable amplitude bias pulse source 133. Thus,illustratively, the windings of conductor 12% are merely shifted twolegs from those of conductor 12%. Similarly, a conductor 134 is coupledserially and in an alternating sense to each of legs 115, 116, 113 and114 in that order by way of windings 135 136 137 and 138 respectively,and is connected to vari able amplitude bias pulse source 133. Controlmeans 139 activates the pulse sources 126 and 133 to move through theregister information supplied by a conventional pulse generating input140 to leg 113 by way of conductor 141. Magnetic isolation between setsof legs is provided during operation by Way of conductors 142 and 14%including related sets of figure 8 windings through the even and oddapertures 120, respectively, (shown for convenience only throughapertures 129 and 120 Conductors 142 are connected to drive source 126by way of conductor 127,, and 127 to be activated alternately 3 fordriving the flux about the odd or even sets of apertures into thecircular flux path during the corresponding A and B phases of operationas will become clearer hereinafter.

During the first and second cycles of operation, two advance and tworeset pulses as shown in FIG. 3 are applied by sources 126 and 133through the conductors having the subscript (1. Thus, operation duringthese cycles designated the A phase of operation, is initiated in thesets of four legs starting with legs 113 as indicated by the verticallines limiting the A phase designation in PEG. 4. Normally, input source149 saturates legs 113 and 114 In such a case, the first module of theshift register need not undergo first and second cycles of operation asdescribed because legs 115 and 116 will become saturated during thefirst cycle of operation. However, input source 149 could be the outputof some complicated circuit which provides a degenerate flux conditionin legs 113 and 11 1 as described, in which case two cycles of operationper module would be necessary. Accordingly, a versatile shift registerin accordance with this invention includes circuitry which provides inthe first module for the described two cycles of operation.Consequently, whether or not regeneration of the input signal isrequired, the operation is essentially as described in connection withFir-GS. 2 and 3, resulting in a (regenerated) one in leg 116 Magneticisolation between the first and second sets of legs in the A phase ofoperation is achieved by way of gate 123 activated by the pulses appliedto conductor 127 During the third and fourth cycles or the B phase ofoperation as shown in PEG. 4, a second set of two advance and two resetpulses as shown in FIG. 3 are applied by sources 126 and 133 through theconductors having the subscript b. Thus operation during these cycles islimited to the sets of four legs starting with legs 115 similarlyindicated, the transfer of information from one information address toanother requiring one A phase and one B phase of operation. Magneticisolation between the sets of legs 115, 116, 113 and 114, theoperational sets of legs during the third and fourth cycles, or the 8"phase of operation is achieved by way of gates 123 and 123 et cetera,activated by the pulses applied to conductor 127 It is helpful to notethat the basic modules of PEG. 1 overlap each other by two legs whenoperated in the two phase per bit mode of operation described inconnection with the shift register of FIG. 4. Accordingly, leg 113 isthe initial leg of the register and leg 11 i is the terminal leg, theregenerated one being transferred initially to legs 114 by the B phaseof operation. The process repeats until the regenerated one is stored inleg 11 i and activates utilization circuit 147 by way of conductor 1 53.

In the situation where the input source 140 introduces a stored zerofollowing a previously introduced stored one, the flux distributionalready present in the recipient module for example including legs 113,114, .115 and 116 is as shown in FIG. 28. Since a partially switchedflux condition already obtains there, a one condition would beregenerated during the following two cycles of operation unless themodule is reset prior to the introduction of the stored zero.Accordingly, after the A phase of operation terminates or, in otherwords, after the second cycle of operation as shown in FIG. 3, the firsttwo legs of each module in the A phase are driven to the clear state.Similarly, after the B phase or after four cycles of operation, thefirst two legs of each module in the B phase are driven to the clearstate. Means for driving the various legs of a shift register in thismanner are well known in the art. One means shown in FIG. 4 comprises aconductor (not shown) inductively coupled to all legs 114 except theterminal leg of the register. For clarity the inductive coupling isshown illustratively by winding 14%,, about log 114 only. The conductoris connected to any conventional pulse source (not shown) suitable forinducing through winding 149 a magnetomotive force in a sense to drivethe flux in legs 114 to saturation in the counterclockwise direction orto the clear state as shown in FIG. 1. Similarly, a second conductor(not shown) is inductively coupled to legs 116 shown illustratively bywinding 150 about leg 116 also connected to the same or otherconventional pulse source (not shown) suitable for driving leg 116 tothe clear state.

No effort has been made to exhaust the possible embodiments of thisinvention. It Will be understood that the embodiments described aremerely illustrative of the preferred form of the invention and variousmodifications may be made therein without departing from the scope andspirit of this invention.

What is claimed is:

1. An information transfer circuit comprising a ferrite sheet of amaterial capable of assuming a first and second stable magnetic state,said sheet being apertured to include first, second, third and fourthlegs therein, means for applying to said ferrite sheet alternating firstand second pulses for repeatedly switching between said first magneticstate and said second magnetic state the flux in said second leg, andmeans for alternately select- Bing simultaneously with said first andsecond pulses respectively a flux closure path through said fourth andthird legs for the flux switched in said second leg.

2. An information transfer circuit comprising a ferrite sheet of amaterial capable of assuming a first and second stable magnetic state,said sheet being apertured to include first, second, third and fourthlegs therein, first winding means coupled to said second leg, secondWinding means coupled to each of the four legs, means for applyingalternating first and second pulses to said first winding meansrepeatedly to switch the flux in said second leg between said first andsaid second stable magnetic state and means connected to said secondwinding means for magnetically biasing preselected ones of said legs forselecting a flux closure path through said second and fourth legs duringsaid first pulses and a flux closure path through said second and thirdlegs during said second pulses.

3. An information transfer circuit comprising a ferrite sheet of amaterial capable of assuming a first and second stable magnetic state,said sheet being apertured to include first, second, third and fourthlegs therein, first winding means coupled to said second leg, secondwinding means coupled to the first, third and fourth legs, third windingmeans coupled to each of the four legs, means for applying alternatingfirst and second pulses to said first winding means repeatedly to switchthe flux in said second leg between said first and said second stablemagnetic state, means connected to said second winding means formagnetically biasing said first, third and fourth legs for selecting aflux closure path through said fourth leg for the flux switched in saidsecond leg during said first pulses, and means connected to said thirdwinding means for magnetically biasing preselected ones of said legs forselecting a flux closure path through said third leg for the fluxswitched in said second leg during said second pulses.

4. An information transfer circuit comprising a ferrite sheet of amaterial capable of assuming a first and second stable magnetic state,said ferrite sheet being apertured to form first and second spaced apartside rails interconnected by first, second, third and fourth transversespaced apart legs thus defining a sequence of three apertures, saidfirst side rail including a fourth aperture adjacent the second apertureof said sequence of three aperture defining a circular flux paththereabout, means for applying to said ferrite sheet first and secondpulses for repeatedly switching between said first and said secondstable magnetic state the flux in said second leg, means for alternatelyselecting simultaneously with said first and second pulses respectivelya flux closure path through said fourth leg and through said third legfor the flux switched .in said second leg, and means for alternatelyswitching simultaneously with said first and second pulses respectivelythe flux in said circular flux path between the circular path and a pathin the direction of said fourth leg.

5. An information transfer circuit comprising a ferrite sheet of amaterial capable of assuming a first and second stable magnetic state,said sheet being apertured-to form first and second spaced apart siderails interconnected by first, second, third and fourth transversespaced apart legs thus defining a sequence of three apertures, saidfirst rail including therein a fourth aperture adjacent the second ofsaid sequence of three apertures defining a circular flux paththereabout, first winding means coupled to said second leg, secondwinding means coupled to each of the four legs, third winding meanscoupled to said first side rail at said fourth aperture, means forapplying alternating first and second pulses to said first winding meansrepeatedly to switch the flux in said second leg between said first andsaid second stable magnetic state, means connected to said secondwinding means for magnetically biasing preselected ones of said legs forselecting a flux closure path through said second and fourth legs duringsaid first pulses and a flux closure path through said second and thirdlegs during said second pulses, and means connected to said thirdwinding means for alternately switching simultaneously with said firstand second pulses respectively the flux in said circular path betweensaid circular flux path and a path in the direction of said fourth leg.1

6. An information transfer circuit comprising a ferrite sheet of amaterial capable of assuming a first and second stable magnetic state,said sheet being apertured to form first and second spaced apart siderails interconnected by first, second, third and fourth transversespaced apart legs thus defining a sequence of three apertures, saidfirst side rail including therein a fourth aperture adjacent the secondof said sequence of three apertures, first winding means coupled to saidsecond legs, second winding means coupled to said first, third andfourth legs, third winding means coupled to each of the four legs,fourth winding means coupled to said first side rail at said fourthaperture, means for applying alternating first and second pulses to saidfirst winding means repeatedly to switch the flux in said second legbetween said first and said second stable magnetic state, meansconnected to said second Winding means for magnetically biasing saidfirst, third and fourth legs for selecting a fiux closure path throughsaid fourth leg for the flux switched in said second leg during saidfirst pulse, means connected to said third winding means formagnetically biasing said four legs for selecting a flux closure paththrough said third leg for the flux switched in said second leg duringsaid second pulse, and means connected to said fourth winding means foralternately switching simultaneously with said first and second pulsesrespectively the flux in said circular flux path between the circularpath and a path in the direction of said fourth leg.

7. An information transfer circuit in accordance with claim 6 whereinsaid second Winding means comprises an electrical conductor inductivelycoupled to said first and third legs in the same sense and to saidfourth leg in the opposite sense, and said third winding means comprisesan electrical conductor inductively coupled to said first, second, thirdand fourth legs serially in an alternating sense.

8. A shift register comprising a ferrite sheet of a material capable ofassuming a first and second stable magnetic state, said sheet beingapertured to form a plurality of sets of first, second, third and fourthlegs, and means for incrementally driving the fourth leg of each of saidplurality of sets of legs to a stable magnetic state, said meanscomprising first winding means coupled to the second of each of saidsets of legs, second Winding means coupled to each leg of each of saidsets of legs, means for applying to said first winding means first andsecond pulses for repeatedly switching the flux in each second leg, andmeans for applying to said second winding means 11 r third and fourthpulses synchronous with said first and second pulses for magneticallybiasing preselected ones of said legs for selecting alternately a fiuxclosure pat-h first through the fourth leg and second through the thirdleg of each of said sets of legs for the fiux switched in thecorresponding second leg during said first and second pulsesrespectively.

9. A shift register comprising a ferrite sheet of a material capable ofassuming a first and second stable magnetic state, said ferrite sheetbeing apertured to form first and second side rails and a transversesequence of interconnecting legs defining thercbetween a first sequenceof apertures, said first side rail including a second sequence ofapertures one adjacent every second aperture of said first sequence ofapertures and each defining thereabout a circular flux carrying path,each of said second apertures being defined by a first and second leg ofsaid first sequence of legs, each successive four legs starting witheach of said first legs constituting a set of legs, means forincrementally driving the flux in the fourth legs of each of said setsof four legs to a stable magnetic state, said means comprising means forapplying first and second pulses to said ferrite sheet for repeatedlyswitching between said first stabie magnetic state and said second theflux in each of said second legs, and means for alternately selectingsimultaneously with said first and second pulses respectively a fluxclosure path through the fourth and third legs of said set of four legsfor the flux switched in said second leg, input means for introducinginformation to the first leg of the first set of four legs, andutilization means for accepting information from said fourth leg of theterminal set of four legs.

10. A shift register comprising a ferrite sheet of a material capable ofassuming a first and second stable magnetic state, said sheet beingapertured to form a plurality of sets of first, second, third and fourthlegs, and means for incrementally driving the fourth leg of each of saidplurality of sets of legs to a stable magnetic state, said meanscomprising first winding means coupled to the second leg of each of saidsets of legs, second winding means coupled to each first, third andfourth leg of each of said sets of legs, third winding means coupled toeach leg of each of said plurality of sets of legs, means for applyingto said first winding means first and second pulses for repeatedlyswitching the fiux in each second leg, means for applying to said secondwinding means third pulses synchronously with said first pulse formagnetically biasing each first, third and fourth legs to preselect eachfourth leg as the flux closure path for the flux switched in each secondleg during said first pulses, and means for applying to said thirdwinding means fourth pulses synchroously with said second pulses formagnetically biasing each first, second, third and fourth legs topreselect each third leg as the flux closure path for the fiux switchedin each second leg during said second pulses.

11. A shift register comprising a ferrite sheet of a material capable ofassuming a first and second stable mag netic state, said sheet beingapertured to include first and second side rails interconnected by aplurality of operational sets of first, second, third and fourth legsforming therebetween a sequence of apertures divisible into sets ofthree apertures, said first side rail including an additional apertureadjacent every other aperture of said sequence of apertures, said shiftregister being operated in first and second phases, means for selectingalternately said first leg and said third leg as the initial legs ofsaid o erational sets of legs during said first and second phasesrespectively, first winding means coupled to each second leg of each setof legs in each phase, second winding means coupled to each first, thirdand fourth legs of each set of legs in each phase, third winding meanscoupled to each first, second, third and fourth legs of each set of legsin each phase, means for applying to said first winding means first andsecond pulses repeatedly to switch said second leg, means for applyingthird pulses to said second winding to magnetically bias said first,third and fourth legs for selecting said fourth legs as the flux closurepath for the flux switched in said second legs during said first pulses,means for applying fourth pulses to said third Winding to magneticallybias said first, second, third and fourth legs for selecting said thirdlegs as the fiux closure path for the flux switched in said second legsduring said second pulses, means for applying fifth and sixth pulses tosaid first side rail at said additional aperture synchronously with saidfirst and second pulse respectively for switching the flux in thecircular flux path thereabout toward said fourth leg and back again, andmeans for alternating between said first and second phases.

12. A shift register in accordance with claim 11 including an inputmeans connected to the rst leg of the first operational set of legs insaid first stage, and including a utilization circuit connected to thefourth leg of the last operational set of legs in said second phase.

13. A shift register in accordance with claim 12 including a fifthwinding means coupled to said first side rail at said additionalapertures, and means connected to said first fifth winding means forholding fixed in said circular path the flux at the additional aperturesadjacent the fourth leg of each set of legs during said first phase andholding fixed in said circular path the flux at the additional aperturesadjacent the fourth leg of each set of legs during said second phase toisolate magnetically the operational sets of legs of the current phasefrom the corresponding next preceding and next succeeding legs.

References Cited by the Examiner UNITED STATES PATENTS 3,048,826 8/62Averill 340-174 3,050,715 8/62 Stabler 340-474 IRVING L. SRAGOW, PrimalyExaminer.

3. AN INFORMATION TRANSFER CIRCUIT COMPRISING A FERRITE SHEET OF AMATERIAL CAPABLE OF ASSUMING A FIRST AND SECOND STABLE MAGNETIC STATE,SAID SHEET BEING APERTURED TO INCLUDE FIRST, SECOND, THIRD AND FOURTHLEGS THEREIN, FIRST WINDING MEANS COUPLED TO SAID SECOND LEG, SECONDWINDING MEANS COUPLED TO THE FIRST, THIRD AND FOURTH LEGS, THIRD WINDINGMEANS COUPLED TO EACH OF THE FOUR LEGS, MEANS FOR APPLYING ALTERNATINGFIRST AND SECOND PULSES TO SAID FIRST WINDING MEANS REPEATEDLY TO SWITCHTHE FLUX IN SAID SECOND LEG BETWEEN SAID FIRST AND SAID SECOND STABLEMAGMETIC STATE, MEANS CONNECTED TO SAID SECOND WINDING MEANS FORMAGNETICALLY BIASING SAID FIRST, THIRD AND FOURTH LEGS FOR SELECTING AFLUX CLOSURE PATH THROUGH SAID FOURTH LEG FOR THE FLUX SWITCHED IN SAIDSECOND LEG DURING SAID FIRST PULSES, AND MEANS CONNECTED TO SAID THIRDWINDING MEANS FOR MAGNETICALLY BIASING PRESELECTED ONE OF SAID LEGS FORSELECTING A FLUX CLOSURE PATH THROUGH SAID THIRD LEG FOR THE FLUXSWITCHED IN SAID SECOND LEG DURING SAID SECOND PULSES.